Effectively Inhibiting Charge Injection and Dielectric Loss of High Permittivity Inorganic Materials by Rationally Coating Organic Polymer for Achieving High Output Charge Density

Although high permittivity of inorganic materials (possibly two orders larger than organic polymers) is theoretically considered as ideal triboelectric materials, their high leakage property and low contact potential difference with metal electrodes lead to failure to obtain high triboelectric charge density. Besides, the internal space charge accumulation as a result of their defect levels reduces the output charge density and causes dielectric loss or even dielectric breakdown under charge injection in charge-excitation triboelectric nanogenerator (CE-TENG). Herein, this study proposes high permittivity and low dielectric loss inorganic materials as triboelectric layers. In order to prevent charge injection passing through the surface of inorganic materials caused by air breakdown under charge excitation, an organic polymer is coated, which has high permittivity, big polarizability, none charge traps, and large work function difference with metal electrodes. After optimizing the high dielectric inorganic layer and the coated organic polymer layer, the output charge of CE-TENG based on 1 mm PZT-5H coated with P(VDF-TrFE-CFE) achieves 2.83 mC m-2, 6.5 times of CE-TENG based on 1 mm PZT-5H, breaking the historical record for inorganic material TENG. This work clarifies the material selection criteria for CE-TENG and provides a deeper understanding of charge transfer mechanism of inorganic materials. This paper proposes high permittivity and low dielectric loss inorganic materials as triboelectric layers. To prevent charge injection through the surface of inorganic materials caused by air breakdown, an organic polymer is coated, which has high permittivity, big polarizability, none charge traps, and large work function difference with metal electrodes. image